Recently, it has been proposed to use an electroconductive film with a mesh pattern formed thereon of thin metal wires as an electromagnetic-wave shield film (see Japanese Laid-Open Patent Publication No. 2009-252868 and Japanese Laid-Open Patent Publication No. 2010-276998).
Japanese Laid-Open Patent Publication No. 2009-252868 describes that a mesh-shaped electroconductive layer is formed with varying mesh line widths on a transparent substrate by gravure printing. For example, it is stated that mesh line widths are formed alternately in maximum and minimum values in at least some mesh region. The electroconductive film is described as being able to provide a light-transmitting electromagnetic-wave shield material that has an excellent electromagnetic-wave shielding capability and is almost free of the generation of moire.
Japanese Laid-Open Patent Publication No. 2010-276998 describes that a photosensitive material is subjected to proximity exposure through a photomask that is spaced by a proximity gap in the range from 70 to 200 μm, fabricating a mesh pattern of thin metal wires. In particular, it describes that bulging portions that bulge toward openings are randomly formed on the sides of thin metal wires between crossings for thereby suppressing moire.